Resolvers are electrical devices that are most often used as angle measurement transducers. Various types of resolvers have been developed in order to reduce their size and increase their performance.
One type of resolver includes insulating members. To connect to the resolver, pins are included in an extension part of an insulating member. The wires of the stator coil of the resolver connect to the pins, as do the lead wires or an electrical connector on the resolver. An example of such a resolver is disclosed in Japanese Unexamined Patent Application Publication H 10-309067. Making the resolver smaller reduces the amount of insulating material. But because the extension part with the pins is integrated into the insulating member a smaller amount of insulating material renders the extension part more susceptible to breakage when making an electrical connection to the resolver.
Other types of resolvers include connectors with male or female connector pins that are integrated with an insulating cover of the resolver. An example of such a resolver is disclosed in Japanese Unexamined Patent Application Publication 2001-330472. The integration of the pins with the insulating cover makes the connectors mechanically stronger. As such, external connectors may be attached and removed from the resolver with ease. The wires of the stator coils connect to the pins. But because the pins are integrated with insulating cover, reducing the size of such resolvers is difficult.
Yet other types of resolvers have terminal holders within notched parts on the outer periphery of a ring-shaped stator. An example of such a resolver is disclosed in Japanese Unexamined Patent Application Publication 2001-56237. The lead lines to the resolver are along the axial direction of the stator. For these types of resolver, the various corners on the resolver are flat, resulting in a thinner structure with a smaller diameter.
Further, all the above-described resolvers operated at normal temperatures and could not withstand high temperatures. An example of a high temperature resolver is shown in FIG. 8. The stator of the resolver includes a stator core 100 comprising multiple layers of plates. Stator magnetic poles 104 protrude from the stator core 100 towards the center of the yoke of the resolver and have multiple stator magnetic pole teeth 103. The wires of the stator coils (not shown) wrap around the stator magnetic poles 104. Two insulating members 101, 107 are on either side of the stator core 100. The periphery of the stator core 100 includes protrusion parts 102, which in turn include grooves 108 to hold the lead wires 111. The grooves 108 also include terminal plates 105.
FIG. 9 is a diagram illustrating a terminal plate 105. The bottom part of the terminal plate 105 is rooted in the groove 108 and has a rim-shaped weld part 120 at the top of the terminal plate 105. The weld part 120 is bent and has an end of stator coil wire 130 attached to it by resistance welding or high-temperature soldering. The stator coil wire 130 is also wrapped around the top part of the terminal plate 105.
FIG. 10 is a diagram illustrating a lead wire 111. The lead wire 111 has a core 109 and a covering 106. Some of the core 109 may be exposed at the tip of the lead wire 111 by means of a mechanical or chemical process. Returning to FIG. 9, the core 109 is wrapped under the weld part 120 of the terminal plate 105.
The resolver of FIG. 8, however, is hard to miniaturize and manufacture through automation. For operation at high temperature, the insulation on the stator coil wires 130 is highly durable, for example polyamideimide insulation. The connections require resistive welding or high-temperature soldering but the weld part 120 must be large enough to accommodate the electrode of the resistive welder. Also, as the terminal plates 105 are in the grooves 108 during welding or soldering, it is difficult to reduce the size of terminal plates 105.
Additional problem with miniaturizing the resolver of FIG. 8 include the removal of insulation on the stator coil wires 130 in order to perform high-temperature soldering. The mechanical or chemical method for removing the insulation may affect the reliability of the resolver. Also, the automatic winding equipment for winding the stator coil wires 130 on such a resolver may be complicated.